The present disclosure relates generally to systems for shading windows, and more specifically, to variable light transmission shade systems for use in vehicles.
At least some known vehicles include shade systems that cooperate with the vehicle windows. For example, in some vehicles, the window is a roof window that is fixed or that is movable (sometimes referred to as a “sunroof” or a “moonroof”). In some vehicles, the shade system is manually actuated. In other vehicles, the shade system is power-driven, and may be actuated through a control interface device accessible within the passenger compartment of the vehicle.
At least some known shade systems include an assembly that is mounted between the roof-mounted window and the passenger compartment. The shade system includes two side rails, and a pair of cross members. A shade member is secured at a first end to a shade roll, for sliding movement back and forth along the side rails, and is secured at a second end to the first cross member. A drive system moves the shade roll along the slide rails to selectively move the shade roll away from the first cross member and towards the second cross member, thus causing the shade member to be unrolled from the shade roll. A tension or retractor spring is coupled to the shade roll to retract the shade roll towards the first cross member, and to cause the shade member to be rolled up on the shade roll. The tension spring also maintains tension in the shade member, after the shade roll has moved to a predetermined position. Because the shade roll is pushed or pulled by the drive system, noise and/or vibration may be created during operation as the shade roll is forced to overcome sliding friction while moving along the side rails. In addition, such shade systems are often only positionable either open or fully closed.
In at least some known shade systems, the shade member is typically one of two types. The first type of shade member uses a light blocking fabric to substantially prevent all light from passing through. The second type of shade member is a mesh layer that allows a predetermined amount (e.g., typically less than five percent) of the total light striking the shade member to pass therethrough. Neither of these types of shade member has variable light permeability, such that the amount of light allowed to pass through the shade member is fixed.